Microphone



(No Model.)

S. D. HOUPT. Microphones. No. 230,550. Patented July 27,1880.

' To all whom it may concern NITED STATES SAMUEL D HOUPT, OF FINDLAY, OHIO.

MICROPHONE.

SPECIFICATION forming part of Letters Patent No. 230,550, dated July 27, 1880. I Application filed March 5,1sso. (No model.)

Be it known that I, SAMUEL D. HOUPT, of Findlay, in the county of Hancock and State of Ohio, have invented certain new and usefulImprovements in Microphones; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon,

which form a part of this specification.

This invention relates to certain improvements in microphones or telephonic transmitters; and it has for it objects to provide a means by which the internal parts of the device may be conveniently reached for the purpose of adjustment; to secure better articulation than in the transmitters as heretofore constructed to prevent the objectionable rattling or grating noise consequentupon theindependent vibration of the spring carrying the contact-maker; to provide an improved means of adjustment for the contactniaker and to prevent the usual inequalities of the contact-surfaces of the diaphragm or disk and the contact-maker consequent upon the burning of the carbon contact-surfaces when subjected to the passage of an electric current. These ob- 0 jects l attain by the mechanism illustrated in the accompanying drawings, in which- Figure 1 represents a front view of my improved microphone with the front of the easing open, showing the internal mechanism. Fig. 2 is a vertical sectional view, and Fig. 3 a horizontal section, showing the casing and front in an open position to expose the internal parts for adjustment; and Fig. 4, a detached view of a modification of the contactmaker.

The letter A indicates the casing of a microphone or telephonic transmitter, consisting of a base, B, to be attached to a wall or other support in any convenient manner, and O a rectangular frame, open at both sides and attached at one side to the base A by means of hinges D, the said frame being provided with a front, E, which is attached to the opposite side of the frame 0 by hinges F.

The frame 0 is provided at one side with a lock, G, which is adapted to engage a staple,

H, secured to the base A, and the front E with a staple, I, with which is adapted to engagea hook, K, whereby the parts of the casing can be securely locked to protect the internal mechanism.

I The front E is provided with an aperture, L, and with a diaphragm or carbon disk, M, a concave-convex carbon disk being illustrated in the present case. The said front also carries a slotted standard, N, secured thereto in any convenient manner, in which is pivoted a block, 0, to which is secured an adjustable slot-ted fiat spring, P, by means of a clamping-screw, R, passing through the ,slot in the spring into the block 0. The said clampingscrew also serves to secure to the said block a curved spring, S, the free end of which bears against the standard and operates to throw the contact-maker away from the diaphragm or disk.

The letter T indicates a set-screw passing through the standard N and bearing against the block 0, by means of which the contactmaker may be brought to bear against the diaphragm or disk with any desired pressure for the purpose of adjustment; j r

In order to prevent or deaden any vibration of the spring P independent of the vibration of the disk or diaphragn1,frorn any cause whatever, which gives rise to the disagreeable rattling or grating noise at the receiving-instrument, which so materially interferes with distinet articulation, the spring is enveloped in an elastic coating or casing of rubber, guttapercha, or other similar material, which prevents the vibration of the spring itself, and at the same time permits, through the springbearing, the proper variation in the intensity of the electric current between the diaphragm or disk and the contact-maker. This object is further aided by the peculiar construction of the contact-maker, which is in the form of a heavy disk, A, carrying the carbon button B, the weight of the disk serving to prevent the spring which carries the contact-maker from vibrating, except when put in motion by the vibration or sound waves transmitted through the diaphragm or disk.

The elastic casing of rubber or the like material and the weighted disk B, (shown in connection herewith,) do not form a part of this application, and are not claimed herein; but they are hereby reservedfor a future separate application now in process of preparation.

()ne of the most serious objections experienced in the use of two carbon contact-surfaces is that the bearing-faces become irregularly worn by the burning of the carbon at the points of contact, rendering frequent adjustment necessary. To obviate this, and at the same time secure the full resistance of carbon which is necessary for the proper workin g of a microphone, I employ a metallic contact-point, G, which is set in a recess in the contact-maker and bears against the disk or diaphragm, as shown in Fig. 20f the drawings.

The metallic contact-point is flush with the.

face of the carbon contact-maker, so that the said metallic contact-point and the face of the carbon contact maker will both bear against the carbon disk or diaphragm. By this means the resistance of the carbon is secured, and at the same time sufficient conductivity at the points ofcontact is maintained to prevent the electric current, when very strong and long maintained, from burning and wasting the carbon.

The disk or diaphragm and the contact-maker are connected with a battery and the primary circuit of an induction-coil, D, in the usual manner, the secondary circuit being connected with the main line leading to the receiving-instrument at a distant station.

The connections of the diaphragm and contactmaker with the coil and battery are through the hinges at the base and front of the casing, so that said connections will remechanism may be conveniently reached for adjustment, substantially as specified.

2. In combination with the casing of a microphone or telephonic transmitter and the diaphragm or disk thereof, the standard havin g pivoted thereto a spring carrying the contact-maker, and the spring and set-screw for adjusting said contact-maker with respect to the diaphragm or disk, substantially as and for the purpose specified.

3. In combination with the carbon disk of a microphone or telephonic transmitter and the carbon contact-maker, the metallic contact point inserted in said contact-maker and bearing against the carbon disk, the said metallic contactpoint being flush with the face of the carbon contact'maker, substantially as and for the purpose specified.

In testi ny that I claim the foregoing I have hereunto set my hand this 14th day of January, 1880.

S. D. l-IOUPT. Witnesses:

THEO. MUNGEN, I1. J. ENNIs. 

